Ubuntu – How to adjust charging thresholds of laptop battery

There may be. Some 'proprietary' extensions which allow to operate on battery. For example tp-smapi patchset allows to set the maximum charging threshold for thinkpads. Setting it to 0 would prevent it from charging.

Some laptops may not have that possibility in BIOS so you need to post details about hardware to receive any details.

This is a common issue with Thinkpad laptops with dual batteries.

When you plug in your laptop it will start by charging BAT0 while BAT1 reports a unknown state. BAT1 will report a charging state when BAT0 is full and BAT1 actually starts charging.

You need to take this into account in your script, and combine values for BAT0 and BAT1 to have something usable :

battery_level=$(("$battery_level_0 + $battery_level_1"))
battery_max=$(("$battery_max_0 + $battery_max_1"))

battery_percent=$(("$battery_level * 100"))
battery_percent=$(("$battery_percent / $battery_max"))

Here is a full example :

#!/bin/sh

path_ac="/sys/class/power_supply/AC"
path_battery_0="/sys/class/power_supply/BAT0"
path_battery_1="/sys/class/power_supply/BAT1"

ac=0
battery_level_0=0
battery_level_1=0
battery_max_0=0
battery_max_1=0

if [ -f "$path_ac/online" ]; then
    ac=$(cat "$path_ac/online")
fi

if [ -f "$path_battery_0/energy_now" ]; then
    battery_level_0=$(cat "$path_battery_0/energy_now")
fi

if [ -f "$path_battery_0/energy_full" ]; then
    battery_max_0=$(cat "$path_battery_0/energy_full")
fi

if [ -f "$path_battery_1/energy_now" ]; then
    battery_level_1=$(cat "$path_battery_1/energy_now")
fi

if [ -f "$path_battery_1/energy_full" ]; then
    battery_max_1=$(cat "$path_battery_1/energy_full")
fi

battery_level=$(("$battery_level_0 + $battery_level_1"))
battery_max=$(("$battery_max_0 + $battery_max_1"))

battery_percent=$(("$battery_level * 100"))
battery_percent=$(("$battery_percent / $battery_max"))

if [ "$ac" -eq 1 ]; then
    plug=""

    echo "$plug $battery_percent %"
else
    if [ "$battery_percent" -gt 95 ]; then
        echo ""
    elif [ "$battery_percent" -gt 85 ]; then
        icon=""
    elif [ "$battery_percent" -gt 60 ]; then
        icon=""
    elif [ "$battery_percent" -gt 35 ]; then
        icon=""
    elif [ "$battery_percent" -gt 10 ]; then
        icon=""
    else
        icon=""
    fi

    echo "$icon $battery_percent %"
fi